-LRB- CNN -RRB- -- San Francisco 's new sheriff is facing misdemeanor charges over an alleged domestic abuse incident on New Year 's Eve , authorities said .

Sheriff Ross Mirkarimi , who was sworn in Monday , said Friday he will not resign .

`` We are cooperating with law enforcement and the district attorney 's office and will , of course , continue to do so , '' he told reporters .

The charges were announced by San Francisco District Attorney George Gascon , who also took office Monday .

Mirkarimi is accused of domestic violence with battery , child endangerment and dissuading a witness .

Gascon said there were a series of text messages between the sheriff and his wife , Eliana Lopez , the alleged victim , about the incident .

Lopez , standing next to her husband , called the charges `` unbelievable '' and said the couple would fight them .

`` I do n't have any complaint against my husband , '' Lopez said . `` We are together . ... this is completely wrong . ''

Mirkarimi was booked and released on bail , San Francisco police said .

Mayor Edwin M. Lee called the charges `` extremely serious and troubling . ''

`` As elected officials , our primary responsibility and focus must always be to fulfill our duties to the people of San Francisco , '' Lee said in a statement .

He said he would review options under the city charter , but `` ensure that we do not take steps that undermine the integrity of the criminal justice proceedings under way . ''

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Sheriff 's wife says couple will fight allegations

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Mayor calls charges `` extremely serious and troubling ''

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Ross Mirkarimi is accused of domestic violence